But it's a cost shared by all open shells, right? Well, even if it was 15MB per shell session, it should still be worth it if the startup and searching is faste

But it's a cost shared by all open shells, right? Well, even if it was 15MB per shell session, it should still be worth it if the startup and searching is faster. For comparison: I use extended ZSH history format, which records a timestamp and duration of the call (and nothing else), and I have ~65k entries there, with history file size, as mentioned, 3.8MB. It could be an order of magnitude larger and I still wouldn't care, as long as it loads faster than it takes ZSH to parse its history file.